The invention relates to a freight loading system for loading and unloading a cargo deck and a method for determining a movement of a freight item on a cargo deck of an aircraft.
For air freight transport, the freight items to be transported, in particular containers or pallets which are preferably made to specific standards, are attached inside the hold by means of lock elements on the cargo deck of the hold. Such lock elements frequently form freight loading tracks between which the standardised freight items can be positioned. To position the freight items at the locations provided for them, freight loading systems are used which support the ground staff in loading and unloading. These freight loading systems accelerate the loading and unloading process. Furthermore the freight loading systems must be very simple to operate as ground staff frequently have no training in a particular freight loading system. In addition both loading and unloading take place under high pressure of time, whereby incorrect operation can easily occur.
A faulty freight loading system, either because of incorrect operation or because of natural wear, can lead to substantial costs as it is very costly to shut down high capacity aircraft. Every minute which a high capacity aircraft spends on the ground costs the operator money.
Frequently freight items are loaded onto a cargo deck which has dimensions such that it is necessary to rotate the freight items, in particular in the area near the door. For this, the area near the door—called the loading and unloading area—is fitted with special function elements comprising freight transport devices (e.g. PDU's, power drive units) and roller mats. There are various strategies for rotating freight items in the physically very restricted loading and unloading area. Corresponding freight loading systems for rotating freight items are known from U.S. Pat. No. 4,050,655, DE 10 2005 008 443 B4, DE 10 2005 021 078 B4, DE 10 2008 052 468 A1 and DE 101 58 298 C1.
It has been shown that irrespective of strategy used to rotate the freight item on the cargo deck, the freight transport devices used are subject to very high wear. Furthermore the process takes a lot of time.
In a design consideration of the freight loading systems used here, it has been found that the loading and unloading area must be designed in a very complex manner. Here frequently freight transport devices of very large dimensions must be used which require separate sealing.